ZKL: Skirmish tab for offline vs bot

99% working. support all mod (including mission) & spring.
Pros: do what it suppose to do (create game vs AI).
Cons: some suggestion is not implemented (like saving previous settings, default setting, and auto startposition). No auto-download (unless somehow you can manually enter new map/mod into the combo-box).

*generated startscript is used to run Spring & also stored in Spring data-dir as "script.txt".
*Its UI is 99% recycled from current Battle room, similar layout, icons, menu and shortcuts. 100% ZKL-esque (plus: startposition can be moved using mouse)

Added a shortcut button at "tool" row in Setting tab, beside benchmarker.

![skirmishtab](https://cloud.githubusercontent.com/assets/2525365/4606502/82f33172-5221-11e4-810d-0103eaaefd5d.jpg)
P/s: neat window shortcut: point at map combobox & use scrollwheel to rapidly browse thru all map